The Study Of Curve Mesh And Optimization Of Node Number In Sheet Metal Forming Simulation

Numerical simulation of sheet metal plastic forming processes can be described as metal flow during forming processes and provide field variables' distribution and movement laws of the deformed body and the die. The simulation can reduce the times of trial and error and provide the guidance on die design. It is important for numerical simulation.Finite element mesh generation is one of critical techniques for FEM. Good meshes help to increase computational speed and precision. Node number optimization can reduce the bandwidth of the sparse matrix and improve the computational speed. Finite element mesh and node number optimization are studied primarily in this paper, some work are done as follows:1) The exploitation of curve mesh is made in the UG, the function menu of curve mesh is added, the process of meshing is more simply, the speed of meshing is faster especially for the complex curve model after expatiating and analyzing some basic ways of mesh generation, such as, mapping approach, node connection approach, topology decomposition approach, octree technique, scanning approach, grid-based approach etc.2) The global stiffness matrix is symmetric, sparse and banded. Reducing the difference between node numbers of the same element can reduce the bandwidth of the sparse matrix and improve the computational speed. For the aim a new algorithm for node number optimization is put forward in this paper by analyzing the peculiarities of the best node number based on induction, it reduces largely the complexity of program and is easily realized by the way that the restrictions become into one restriction by punishment method. The algorithm is suitable for triangle element and shell element of sheet metal forming by taking some examples, it validates the validity and advantage of the algorithm.3) To share the data of FEA model effectively and fully is very difficult; it confines severely the development of numerical simulation now. To use the advantage of CAD and CAE software respective for improving themselves, it can void losing a great deal of data and reduce the time-consuming and exhausting reparation which is done in the CAE software. The paper just primarily study on the data integration of CAD & CAE by converting the data of element and node.4) Taking example of J117 floor of JiangLin CAR to mesh and optimize the node number by using the function of mesh and the program of node number optimization exploited in the paper, to complete the simulation in the DYNAFORM and compare the results of initialization to the results of optimization, it validates ulteriorly the feasibility, validity and advantage of the exploitation.There are two innovations in the paper as follows:1) The exploitation of curve mesh is done in the UG, the function menu of curve mesh is added, the process of meshing is more simply, the speed of meshing is faster especially for the complex curve model2) A new algorithm for node number optimization is put forward in this paper by analyzing the peculiarities of the best node number based on induction, it reduces largely the complexity of program and is easily realized by the way that the restrictions become into restriction by dealing the coefficient. The algorithm can largely reduce the bandwidth of FEM and is more effective for the CAE software itself s node number optimization function.